Grinding tool



April 12 1927.

P. L. .STARR GRINDING 'i'ooL Filed 061:. 10. 1923 2 Sheets-Sheet 1 April 12 1927, 1,624,634

P. L.'-*5TARR I GRINDING TOOL Filed Oct. 10. 1925 2 sheets-sheet 2 ll VENTOR Patented Apr. 12, 1927.

"iPERL? wnsrmim; on GH-IGAGOJ ILLINOIS.

enmnmejoon Application filt l'october. 10/1823. Se'rialNo. 667,681.

This invention re'lates toneW and usefnl *hnprovements in 'iibra sivePinstruments and more particularly to a I grinding machine nda'ptechior use in'grinding and trueing the cylindrical surface ofpist'ons used infvarious'types of motors. Them-am object of my invention is theprovision of a,'grinding instrument having the several parts thereof so constructed and-.erranged as to bring the w itbr'asive or, grinding elements intotight fitting contact with the cylindrical suifaceof the piston so that duringthe grinding action all uneven surfaces W'ill beremoved iroi'n the face c"n:""thev piston and producea sur i 'ace Which is entirely uniform tin-oughout the circumference of the, pi"sto n.

.Aifur'ther object of my invention is the .provision of -a piston grinding instrument wherein the abrasive or grinding elements 1 are applied to the uinea of the rpistonfiin --sucl1;a manner that during the rotation of thejipiston in-its'gririding action the abrasive or grinding members Will contact With "the face of the v piston in such a manner-as to 1 provide ashiftinggninding movement which will tend to produce an entirely smoothand "unbroken. surface on "the 'face; of the piston. ilVith the above and other. objects in view the invention consists in the a-novel' features of construction lthe combination and warrangement of cparts:,hereinafterr more fnlly set 'forth z.1Ii .l..'shown in the accompanying .'d1ra\\"ings, in which:

FFig. 1,. is ia t opoplanzviewof a piston grinder constructed in -.accordance \Vlt-lln'llly invention.

, 'F-ig. 2, 1521 side elevation.

Fig. 3, isma. it 'nnsverse section" taken. on,

the line 3-3, ot'rFig:2, .loo'kingfdown onto the bottom 'su ortinmmember.

in iateralrmovement.

In the construction of my -im' p rove'd device, I provide what will be-knoWn-"as a top amide bottom section, the bottom'- section comprising" two semi-circi' lar plates 1- and Qfthe plate 2, having itormed 'inte ral therewith-an ar1n'3, which maybe suitably secure'd-toany stationary supporting element. Asishovvn inkthe"'draWings the arm 3, is provided "with spaced openings whereby bolts 01- other analogous fastening means may be used for attaching- 'the' machine to a stationary supporting element.

The plates la-ncl"2 ,1are normally retrined in-apara'l'le'led plane'by means of a" heavy coil springb, one end of Which is attached to 21: perforated ear formedc' upon one face of-the plate-1; and its other end detachably "connected wlth the plate 2. From this it- "Will-beapparent that the two sections of, the

b'ottom nemberxmay be moveduaway from each other againstfthe tension :of the spring 5, but :upon' releasing :the two sections"that section. l,;fthroughj the tension of the spring 5; will beunovedback into' position" with respectto the stationary plate 2. p

IFormedQ integrally- With the' plate lfand disposed at 'diametrically opposite points are the semi-circular beaiiing. members *8 and 9a havingoutstanding pinsIr12, disposed below the horizontal plane .oi' .the" bottom sect-ion and the like 'bearin member-s10 an d 11, on section 2, are provided with the outstanding pins 13, which are disposed above the horizontal plane ofthe bottom section, said pins being [disposed-'u-pon opposite sides ofthe center of theflbottom. section and connected by means of ,discs 14 and a'diagonallydisposed bar 14, \tnhi'ch is retained. in position upon the ends of'the pins by means of cotte-rs 115, and laterally held-by a longi'tudineilly bowed spring inember dl'.

From this arrangement 1t Wlll' be apparent that any movement of the section .1; "with Y 'l'espect to section 2, willnot only be up- Wardly but away fromthe section 2, and fa'lso any, movement ofsection; 1, away zfrom' the -stationary. section" 2,"against the tension; of the .coil. springt, will raise the section '1, above. its horizontal alignmentf'vvith the section'l2. 1

The bottom section of the device which includes the plate 1 and 2, is provided with a plurality of sockets 16, which in the present instances are internally threaded to receive the horizontally disposed supporting bolts 17. In connection with the mounting of these bolts 17, I desire to have it understood that while I have shown and described the same as having a threaded connection with the sockets 16, other suitable connections may be used for supporting the bolts with respect to the plates 1 and 2. Mounted upon the bolts 17, are the upstanding supporting bars 18, which are arranged circumferentially of the bottom section. The lower ends of these bars are provided with suitable openings so that they may be loosely mounted for adjustment upon the bolts 17 v In order to provide for this adjustment the suitable adjusting nuts 20, are arranged upon opposite sides of the bar whereby the adjustment of the nuts will move the lower ends of the bars either towards or away from the plates 1 and 2.

It will be apparent that the bolts 17, extend radially from the center of the bottom supporting members and the bars 18, will be moved toward and away from a central point.

The bars 18, in the present instance are each provided with a longitudinal projection 21, arranged intermediate the ends of the bars and formed with a groove 22, in which the grinding stones 3, are arranged. The grinding stones are fitted within the grooves 22, so that a proper amount of the stone extends beyond the face of the projection for contact with the object to be ground.

In order to retain the grinding stones within the grooves 22, I provide suitable retaining members which in the present instance are shown in the form of set screws 24, which extend through the wall of the grooves and have binding engagement with the stones which are arranged within the grooves.

The bars 18, are suitably connected at their upper ends by means of a top section which is formed of two semi circular members 25 and 26. The inner ends of each. of these members are provided with enlarged portions 27 to form suitable bearing surfaces having their outer faces of substantially circular form when the ends of the two sections 25 and 26, are brought together. hen the two members 25 and 26 are arranged with their meeting ends in abutting relation, they are disposed in a substantially horizontal plane above and in spaced relation with the bottom portion of the device.

The member 25, is provided at each end with outstanding bearing pins 12' which are disposed below the horizontal center line of the upper section and the ends of the menr res rear ber 26, are provided with the outstanding pins 13, which are disposed above the hori-v zontal center line of the upper section andmounted upon the pins upon opposite sides of the section are discs 28, said discs being provided with oppositely disposed openings to receive the pins. The discs 28, are retained in position upon the pins by means of the diagonally disposed connecting bars 29, the ends of which are mounted upon the pins and retained in place by means of suitable'wa-shers 30 and cotter pins 15.

In order to eliminate any lateralplay on the part of the ends of the members 25 and 26, I insert between the discs 28 and the bars 29, a longitudinally bowed spring member 31' which is arranged transversely of each of the bars with its ends bearing against the surface of each of the discs at a point upon opposite sides of the pins 12 and 13. 1

It will be apparent from the construction and mounting of the top section that any movement imparted to the member 25, will tend to carry said member not only in a direction away from the member 26, but in a direction above the horizontal plane of the member 26, which movement is carried out simultaneously with the movement of the section 1 of the bottom supporting member.

The member 25, is returned to its former position with respect to the member 26, by means of the coil springs 32 each having one end connected to the perforated ears 33, on the member 25, at a point adjacent each end thereof, while the other ends of the springs are connected to the perforated cars 34, formed on the member 26, at the point adjacent its ends. From this it will be apparent that thetension of the spring members 32 which are arranged upon the inner faces of the members 25 and 26, will have a tendency to normally move the member 25 toward the member 26.

Extending diagonally through the members 25 and 26 and projecting radially from the center of the circle defined by the two members, are the supporting arms or bolts 35, and formed integral. with each of the bolts are the hexagonal shoulders 36 which are adapted for use in adjusting the bolts 35 toward and away from the center of the circle defined by the members25 and 26.

The bolts 35 are threaded througl'i suitable openings in the members 25 and 26, for

adjustment with respect to the said members and are retained in various adjusted positions by means of the lock nuts 37 which are threaded onto tle outer end of the bolts and adapted to be forced into tight the inner ends of the'bolts'f35 a1id"' in mounting the bars upon the' b olts they are"-prefe rably arranged in contact "with one face" of the shoulders" 36 and retained against 311lovement byineans 'Ofthe nuts 38fwhi'ch "are threaded iupon' the inner ends of" the bolts and brought into tight engagement with one face of the bars. It' will he'apparentfron'i this construction "that the upper "section which includes the semi-circular members and 26,, and their eo'opeiative"parts is supported in spaced relation- Vit'h the bottom section by means offlthe bars"l8. It Will also be noted that"in ti'eWjofthestationary support, bf the '1nen1ber"2, "of the bottom section,"the bars which "connect" this member 2 With 1 the member *26, tend to "retain the nein'b'er'Qti against movement,

Whereas the connect-ion between" the inen'r ber 25 and the nieihbe'r lot thebottom sectionwill have a tende cy to inove these two lnenib ers simultaneously carrying the grinding members supported thereby toward and away from the member which s being joperated onby grinding members.

and'other niateriahfro'm corning in contact with the various connections, I provide suitable coverings which "in the presenfiinstanee are illustrated by dotted linesin jhiguresl and 3 These covers are preferablyflproe Vided for the pivotalconnectionsbetween the stationary and-movablesections ofthe top" and bottom portion of the"'devicef'and material andarr anged over the parts so as to enclose the same I sufficiently; to prevent any of the fiying'particles'from coming in contact With'the pivotal connections. a

.I applying this device to a piston or other article-tobe ground it is essentialthat the piston be centrally arranged Within the grinding device and prior/to inserting" the piston between the grlnd'ingunenibers the sections :25 hand 1, are moved in a vertical and la'teral direction which "will tend to Inove thegr'inding rnelnbers desig- ,nated' 1n F 1g, lgas a and "b,"u wa1'd1 and outwardly with respect" to the opposin'g grinding members c 1 and d, thus lea ing suflicient roomto insert'fithei pistonior other lneinber j between the 1 ;finding nembers. After the piston has been placectin position between theggrinding nu bers the sections 1' 21116.25 are releasedand 'the tension of the coilsprin'gs 32 and 5, Wl'll have'a tendency toexert an inwardjpulling movement upon" the sections 1 and 25, and "will inove thefgrinding members ej'and 6 into contact Withthe outer surface of the piston and tend to clamp the p'i stoni'b'etween" all the grinding members so that aluniforin "contact \iiith the suI- acebfthe'pis'tonniaytbebrought about.

"Ai ftertlie piston orloth'er' member to'be 0p- In order to preventpartib'les' 6r abrasive 'set"forth aboiiearotary' movement is im- 'par'td to the :pjston' causing thei'surfa'ce of the sametd travel'over engagingp orti'ons of the fgrin ding 'nieinbers. "Particular 'atten-' tion isdirecte'dito the fact that as the surpresent time, as'far'as I"kno' the grinding:

elements are brought into .direct contact with the surface to be "ground," and through the rotary movement that occurs when grind ing thesu'rface', create a horizontal grinding action. This actloncauses, inthe use 0t coarse stonesa fl grindingelements, the pro- "duet-ion of anun'even surface onthe face" of thepiston," in View "of the fact that particles iot'the" abrasive Of WhiCh grind'ing elenients areformed' WillitraVel infthe same plane,

w'vhfereas', in my de vice'; a Varied grinding I action brougl1t"about"soasto"eli1ninate the forming of any uneven surface Whatever on theface ofthe pistonhnd'produce aper feetly smooth unbroken surface. smooth unbroken surface is produced, due to This the faht that the glfinding action of the "statlona'ry members arid the "movable members oppose "each other in E that 3 the "statioi'iary grinding Inenibers aref imparting a horizon- 'tal fg findingi "movement,Whereas the mov "able grinding nl'enibers are" creating a Vertically shifting "horizontal movement over thesui'tace' of the "piston-Which wilh'have a tendency toehrnlnateany scores caused by the stationary *fineinber's and as the Q'SUi-face of the piston' is grouiidotl' "and": the diameter of the same 1 reduced the grinding t *nieahbeis a and '6, Will continue in their diagonal movement and flthisgrin'ding action acting inoppositionj'tothe grinding action of the stationary grinding members produces" a pertectly' smooth andnnbroken 1 sur- 1, A device for grinding a surfaceof "revcililtion rotation" ofltheork or device, onewithrelationto the other, comprising surfaces adapted to lie' "in i the surface of 'revolutlonot the Work or"'dev1ce, means to support said tools with their hbrading-surfaces insaid "surface" of -"revolution *compris I in b m re i fx lmb r ie' car g 011B 01 and eansto con ect tool or tools each carry may move toward or from the axis of said surface of revolution but in so doing must move axially one member and its tool or tools with reference to another and the tool or tools of the latter.

2. A device for grinding a surface of revolution by rotation of the work or device, one with relation to the other, comprising two or more grinding tools having abrading sun faces adapted to lie in the surface of revolution of the work or device, means to support said tools with their abrading surfaces in said surface of revolution comprising two or more members, each carrying one or more of said tools and means to connect said members so that the members and the tool or tools each carry may move toward or from the axis of said surface of revolution but in so doing must move axially one member and its tool or tools with reference to another and the tool or tools of the latter, said means maintaining parallelism of said tools with said surface of revolution.

3. A device for grinding a surface of revolution by rotation of the work or device, comprising independent members, grinding elements carried by each member, means connecting the members to permit a limited separating movement thereof, said means compelling a relative movement of the members at substantially right angles to the plane of and during such separating movement, and means to normally influence the members against such separating movement.

4. A device for grinding a surface of revolution by relative rotation of the work or device, comprising independent members which together form the substantially circular support, abrading tools carried by each member, yieldable means for normally holding the members together, and means connecting the members and operable in the separation of the members to permit a relative movement of the members in a direction at right angles to the axis of the support while at the same time compelling a relative movement of the members parallel to the axis of the support. I

5. A device for grinding a surface of revolution by rotation of the work or device, comprising independent members which together form a substantially circular sup port, yieldable means for holding the members together, and connecting means between the members operating when the members tend to separate to compel a relative movement thereof which is a component of their movement at right: angles to the axial line,

of the support and their movement parallel to such axial line.

6. A device for grinding a surface of revolution by relative rotation of the work or device, comprising a support formed at the lower end of semi-circular discs and at the upper end of semi-circular sections, springs arranged between the respective discs an between the respective sections to maintain a normal relation of the parts, bars connecting the discs and sections and formed to receive abrading elements, connectors tying the meeting ends of the discs together, connectors tying the meeting ends of the sections together, the mounting of the connectors relative to the discs and to the sections compelling a relative axial movement of the discs and sections under any tendency of the discs and sections to separate against the influence of said springs. I

7. A grinding machine for pistons comprising a device to surround the pistons, said device being made up of two parts yieldingly connected, abrading elements car ried by each part to engage the surface of the pistons, and connectors joining the respective parts and operative to compel a relative movement of the parts axially of the piston during any relative separation of the parts.

8. A grinding machine for pistons comprising a device to surround the pistons and made up of two yieldingly connected parts, abrading elements adjustably carried by said parts, connectors joining the parts to permit a limited separating movement thereof, said connectors bridging the juncture be tween the parts and being normally disposed at an inclination to the horizontal plane of the device, whereby in any tendency of the parts to separate or move together following the separation the connectors will compel a relative movement of the parts axially of the piston.

9. A grinding machine for pistons comprising a skeleton frame arranged to surround the piston and made up of tWo independent parts, springs connecting the parts and tending to normally draw the parts together, abrading tools carried by each part to engage the surface of the piston, pins projecting from the respective parts adjacent their point of juncture, the pins on one part being arranged on a plane above the pins on the other part, and rigid connectors movably engaging the pins, whereby inany tendency of the parts toward a relatively horizontal movement of the connectors compel a relative movement of such parts axially of the piston.

10. A grinding machine for pistons comprising a device to surround the pistons and including two semi-circular plates at the lower end and two semicircular sections at the upper end, springs uniting the plates and sections to maintain them in normal contact on their diametrie edges, bars con necting the united plates and sections, abrading elements carried by the bars to bear upon the piston, pins carried by the plates and by the sections adjacent their respective meeting edges, the pins on one plate and its corresponding section being arranged on a plane above the plane of the pins on the remaining plate and its corresponding' section, and connectors of rigid form loosely engaging the adjacent pins on the plates With similar connectors loosely engaging the adjacent pins on the section, the angular relation of the connectors compelling a relative movement of the connected plates and sections axially of the piston in any tendency of such plates and sections to move against or under the influence of said springs.

In Witness whereof, I hereunto subscribe i5 my name this 6th day of Oct, A. 11,1923. PERL LEE STARR. 

